Airflow how to retry task. Versions of Apache Airflow Providers.

Airflow how to retry task The following topics will refresh your concepts and provide a deeper understanding while using Airflow Task, Airflow Task Instances, DAGs, and DAG Runs. 10. on_execute_callback. An example is not to produce incomplete data in HDFS or S3 at the end of a task. Deployment. Besides that I'd need to check the previous one in case it succeeds so it would branch to the Spark job task and skip the "Start Spark Cluster" task. In that case if for some reason the task from Airflow side is getting terminated (for example worker is restarted) when it respawn the task will retry and reattach to the running remote job. I want these 5 tasks can re-run again. TaskInstance. Note: Non-members can read the full article here. Apr 26, 2017 · When the task is on running state you can click on CLEAR this will call job. If task D fails because of parameter x being too high, I want to rerun task C and task D. skipped: The task was skipped due to branching, LatestOnly, or similar. up_for_retry: The task failed, but has retry attempts left and will be rescheduled. Task B - Generate config file for job. If this service becomes unavailable during the task execution, I would like to retry later (max 3 retries). Invoked when the task is running and Airflow detects two kinds of task/process mismatch: Zombie tasks are tasks that are supposed to be running but suddenly died (e. on_failure_callback. Here are common methods to recover or retry tasks in Airflow if a failure occurs: 1. Thereafter, you can retrieve that data from Xcom in any task across any DAG of your Airflow deployment, including the retry attempt of same / different task Feb 4, 2022 · If the task failed and not is_eligible_to_retry but it belongs to task group (we should be able to access it via self. Sep 1, 2022 · Airflow TaskGroup doesn't support retry, so you cannot retry t1 when t2 fails if they are in the same TaskGroup. About Airflow Tasks; About Airflow Task Instances; 2 Easy Ways to Trigger Airflow DAGs in Apache Airflow. Task A failed once but the retry succeeded and is marked as a success (green). Asking for help, clarification, or responding to other answers. on_retry_callback. I've read about something about: airflow clear -t task_name <dag_name> So think I just have to iterate over the task names clearing them, but I need to know who they are. " from airflow. Anything else. I'm using Airflow but didn't find a way to trigger a task in case the previous one fails. Automatic In Airflow, you can configure individual tasks to retry automatically in case of a failure. Issue. You can call a bash command within the on_retry_callback where you can specify which tasks/dag runs you want to clear. We’ll also provide some tips on how to troubleshoot failed tasks and keep your DAGs running smoothly. 6. Aug 14, 2019 · You can change n to control how many tasks you want to retry before the current task. Jun 26, 2019 · What's the best way to retry an Airflow operator only for certain failures/exceptions? For example, let's assume that I have an Airflow task which relies on the availability of an external service. Here is an example of how to implement a retry mechanism for a task in Airflow: python def my_task_function(**kwargs): Try to run the task. May 16, 2023 · How do the parameters retries, retry_delay and retry_exponential_backoff interact? When there is a retry, when is it scheduled? Exponential backoff sounds interesting, but how does it work? e. operators. Airflow started running the stuck task immediately. Operating System. But you can call a bash command as part of your on_failure_callback and then specify which tasks you want to clear, and if you want downstream/upstream tasks cleared etc. what happens with these parameters? When are the retries scheduled? retries=3, retry_delay=300, retry_exponential_backoff=True Nov 1, 2024 · Would like to ask a Airflow question , currently when we set on the DAG default args to retry 5 times if failure happens default_args = { 'owner': 'testing', 'retries': 5, ' Dec 3, 2019 · Currently, there is no way to set retry at dag level. But that is not running for 5 times. Airflow’s built-in retry mechanism is useful, but it often makes sense to exponentially increase the delay between the tries instead of Apache Airflow's retry mechanism is a fundamental feature that ensures the robustness of data pipeline execution. taskinstance. If task A depends on task B and their start_date are offset in a way that their execution_date don’t line up, A’s dependencies will never be met. Mar 5, 2019 · UPDATE-1. Exponential Backoff for Task Retries Feb 24, 2024 · If the service allows tracking of execution then the Airflow operator can try to reattach to the executed job. Official Apache Airflow Helm Chart. task = PythonOperator( task_id='unreliable_task', python_callable=my_unreliable_function, retries=3, dag=dag ) When a task fails, Airflow will wait for a time interval before retrying the task. But once the schedule kicks off the task it wait to see if the task was successful or not and then update the task instance accordingly. 6, the logic that decides if a task should be retried or not is in airflow. def build_task(self, dag): Feb 2, 2024 · Exponentially increase the delay between task retries. Task E - Process Job results. it can not change the state of taskB to failed. Airflow supports two unique exceptions you can raise if you want to control the state of your Airflow Tasks from within custom Task/Operator code: The current job will be marked as skipped if AirflowSkipException is thrown. Airflow detects two kinds of task/process mismatch: Zombie tasks are tasks that are supposed to be running but suddenly died (e. Aug 16, 2018 · Once the process has "finished", I want it to clear those tasks state(I mean, Failed and Upstream Failed tasks) and retry them automatically. try: do_something_important() except Exception: The task failed. Deployment details. kill() the task will be set to shut_down and moved to up_for_retry immediately hence it is stopped. my_task_function(**kwargs) Q: What are some common causes of task failures in Airflow? Nov 1, 2018 · I made a dag and run an instance of dag. So the task will be rescheduled after it fails. This functionality is crucial for handling transient issues that can occur in distributed systems, such as temporary network outages or resource unavailability. 0: Oct 8, 2024 · Example 1: Restarting a failed task using the `airflow` command. To configure retries, you can set the retries parameter in the task definition. If the job doesn't complete within the configured sensor timeout, the job failed and I want both the start_job and the wait_for_job task to be re-tried. How can I define Operators that can decide if a retry is sensible? In Airflow 1. Mar 11, 2024 · A sensor task (wait_for_job) waits for the job to complete. so I made a change on these tasks. When the task is scheduled, it will check the database to see if the sign-off is done: If the sign-off has not been done yet, the task fails and release the worker and wait for next schedule. Thus, the tasks should produce the same outcome on Dec 29, 2024 · Apache Airflow tasks are structures in the form of DAGs, but there are some scenarios where you might need to kill or Airflow stop DAG tasks. With airflow 2. In this post, you will find out how to fix it. TLDR #2: You can skip directly to the solution, here. . Airflow retries are a fundamental aspect of ensuring the robustness of data pipeline execution. Task D - Run the data manipulation Job. So I connected to the metadata DB and changed backfill_ to scheduled__ in the dag_run row corresponding to the stuck task. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Description - How to run multiple ExternalPythonOperator (I need different packages / versions for different DAG tasks) after each other in serial without being dependent on the previous task's success "upstream_fail". Jul 19, 2021 · Regarding the retry logic: If you specify retries=3 as keyword-argument to your BaseOperator, it will retry 3 times. After implementing retry_exponential_backoff to True there is no failure due to Exceeded rate limits but so far for one run I could see few tasks are still not yet triggered even after the next run executed. 1 show that this doesn't work on Taskflow: @task def test_retries(retries=2): raise ValueError("I failed, please retry") test_retries() Sep 26, 2022 · I have two tasks A and B. their process was killed, or the machine died). If you have a task that failed in Airflow and you want to restart it, you can use the `airflow` command-line interface. This section delves into effective strategies for troubleshooting Apache Airflow tasks, focusing on retry mechanisms and alerting best practices. To set it on the 'safe' side is not desired, as this greatly affects performance in a negative way. Jun 3, 2021 · To do that, from Airflow Web UI: Mark task C as failed; Clear task C with options "upstream" and "failed": This should rerun all failed task (either A or B or any other that is in upstream of C) as well as C (because we marked it as failed). Invoked when the task succeeds. Apr 7, 2017 · If you want to rerun all the subtasks of the failed tasks, there is an easier way than the accepted answer especially if you have multiple tasks you want to rerun. How is that best handled? I'm using AWS MWAA for managed Apache Airflow. find(dag_id=dag_name) dag_runs_sorted = sorted(dag_runs, key=lambda dr: dr. Feb 28, 2020 · As other comments mentioned, I would use caution to make sure you aren't getting into an endless loop of clearing/retries. Jan 18, 2021 · Hi team, There is a use case where I use the subdag operator within which I run tasks in sequence and if one of the tasks managed by subdag fails then I retry the subdag. Can a failed Airflow DAG Task Retry with changed parameter Feb 21, 2019 · You could use the execution_timeout argument when creating the task to control how long it'll run before timing out. How can I set my tasks to rerun on failure as such? I found this question and answer on stack overflow however this only changes the number of retries. Airflow can retry a task if it fails. The execution_timeout attribute can be set for any task, including sensors, to specify the maximum runtime before an AirflowTaskTimeout is raised. When the job fails, the task instance retries. models import DAG from airflow. Apr 28, 2022 · I have a DAG which contains two tasks. Jun 30, 2023 · All the examples of retries on tasks in the Airflow docs are on things like BashOperator. Jul 15, 2021 · In Airflow, how to retry a task only after a condition is met? Related. 9 in celery executor mode. Aug 8, 2018 · In my Airflow DAG I have a task that needs to know if it's the first time it's ran or if it's a retry run. When a task should be retried, it's marked in state up_for_retry. Here’s an example: $ airflow tasks restart --execution-date . Dec 26, 2023 · A: To enable Airflow retry task on failure, you can set the `dag_retry_delay` and `dag_retry_max` parameters in your DAG definition. Hitting this will clear the state of your failed task and allow the scheduler to pick it back up and re-run it. Important Notes If it fails I'd start the "Start Spark cluster" task. 0: There is an option to clear a TaskGroup (see PR) For Airflow<2. Jan 21, 2025 · My requirement is instead of just D retrying, I want to retry the whole task group TG, maybe clear and rerun the whole TG (downstream+recursive). are_dependents_done ( self , session = NEW_SESSION ) [source] ¶ Checks whether the immediate dependents of this task instance have succeeded or have been skipped. Jul 19, 2019 · If you want to re-run a task in Airflow, the best way to do so is to press Clear or Delete (language depends on the Airflow version you’re running), not Run. Azure Kubernetes Services. You can mark the tasks the same as if they were not done ("Clear the state") and make them queued to be re-run. I need to adjust my logic in the task if it's a retry attempt. handle_failure, making it impossible to define the behavior in the operator as it is a responsibility of the task and not the operator. I am using Airflow 2. I would expect Task B to perform normally since Task A retry succeeded but it is marked as upstream_failed and was not triggered. At the third retry it will either mark the task as success if no exception was present or failed if there was an exception. 85 Creating a task¶ You should treat tasks in Airflow equivalent to transactions in a database. How It Works in Airflow. We advise against using dynamic start_date and recommend using fixed ones Jun 9, 2018 · You can mark the downstream task states to success (or failed) to prevent them from running, or mark the entire dag run state to success or failed to stop it from running further. For other failures I do not want to retry. Retry the task. decorators import task @task def extract_data(): # Your data extraction logic here return data Automatic Data Passing with XComs. Manual tests on version 2. But there is another component more suitable for your use case, which is SubDag, it's deprecated but still available in the last version, I think it will be removed once they add its features to TaskGroup (like the retry). get_task_instance(task_id=task_name) with create_session() as session: clear_task_instances(tis=[task_run Sep 17, 2018 · For example, if I have auto retries set to 3 and all 3 fail, there will be 3 tabs in the Airflow UI Logs. Ideally, a task should flow from none, to scheduled, to queued, to running, and finally to success. More often than not, we are all faced with the need to create sets of Tasks we want to either Fail (and retry) or Succeed as a Oct 4, 2022 · Before implementing retry_exponential_backoff the dag was failed due to Exceeded rate limits: too many table update operations for this table. Invoked when the task fails. Lots of thanks! Oct 13, 2024 · Key Exceptions for Apache Airflow Tasks. The `dag_retry_delay` parameter specifies the number of seconds to wait before retrying a failed task, and the `dag_retry_max` parameter specifies the maximum number of times to retry a task before it is Oct 16, 2022 · Let's say we have two DAGs, each containing only one task: DAG A : Task A (produces data, runs manually) DAG B : Task B (consumes hourly data, runs hourly) DAG B runs may fail because hourly data that Task B has to consume is not available yet (not produced by Task A yet). If yes, proceed with the rest of the tasks, and if not, add partition first before proceeding. test_resubmit. Then, you'll want to optionally clear downstream tasks as well and set the state of the relevant DagRun to running. Jun 28, 2021 · In the case the output of A influences whether B succeeds, we should verify the output of task A, inside task A itself. the first four tasks were succeeded but the last task was failed. After that it tries to run the task and then fall back to new retry time. Set up_for_retry for all tasks and run 200 tasks at the same time. For Airflow>=2. Jan 24, 2017 · In my default args for a DAG I have set the retry and retry_delay parameters. Dec 3, 2023 · Once the task is success, airflow should not retry the task. sla_miss_callback. May 15, 2019 · We have a lot of DAGs running on Airflow. How do I trigger all upstream_failed task to "retry" after their parents state changed to success? Dec 3, 2023 · Once the task is success, airflow should not retry the task. If it really is the case that A needs to be re-done when B fails and we can't prevent this, then it would be best to unify the two. Feb 24, 2023 · I'm executing a query that sometimes will fail because of the setting of one parameter. Our task instances are stuck in retry mode. Modify the task schedule in Airflow. This implies that you should never produce incomplete results from your tasks. Mar 4. Is this a way to fix this behavior? The Task B has an ALL_SUCCESS trigger rule. 2 on AWS Dec 27, 2018 · I have a Apache Airflow DAG with tens of thousands of tasks and after a run, say a handful of them failed. the zombie tasks are passed to up_for_retry if they didn't reach the retries which is core. But you can reproduce this by using on_failure_callback and clearing all tasks programatically. Aug 8, 2022 · To fix your problem you can try: from airflow. I have a few ideas on how I Jan 16, 2019 · Task A - Gather the raw data. No Apache Airflow allows users to set timeouts for tasks to ensure that they do not run indefinitely and consume resources. Retries: If a task fails, Airflow automatically retries it based on the defined settings. Is it possible from run 2 of the task for exampl Sep 23, 2024 · How to Use Task Groups in Airflow? Advanced Apache Airflow Patterns: Retry & Failover, SLA Monitoring, and Sensor Tasks. execution_date, reverse=True) dag_run = dag_runs_sorted[0] task_run = dag_run. If it is not supported by Airflow, maybe there is some workaround. Here is my code. Feb 9, 2023 · Airflow will find these periodically, clean them up, and either fail or retry the task depending on its settings. 0. If you could provide some samples that's be great. The conditional check task can either fail or succeed, both are okay. Dec 26, 2023 · In this article, we’ll discuss how to retry tasks in Airflow, including the different retry strategies available and how to configure them. Task F - Generate reports. 4 days ago · In the realm of Apache Airflow, ensuring robust task retry and alerting mechanisms is crucial for maintaining the reliability of your data pipelines. DAG scheduling. It will be under the heading of "Log by attempts". process_2_2) is still in the upstream_failed state. 5. Returns whether a task is in UP_FOR_RETRY state and its retry interval has elapsed. When a task in Airflow fails, the system can automatically retry the task based on the retry parameters defined in the task's configuration. Is there a 'native' way of doing this in Airflow? Apr 21, 2019 · retry_delay (timedelta) – delay between retries; retry_exponential_backoff (bool) – allow progressive longer waits between retries by using exponential backoff algorithm on retry delay (delay will be converted into seconds) max_retry_delay (timedelta) – maximum delay interval between retries Mar 4, 2025 · Failures in data pipelines can occur due to network issues, API timeouts, or transient database failures. task. on_skipped_callback. g. When I monitor the UI, upon a task failure, it briefly changes state to "retry" but immediately following, the DAG state is set to "FAILED" and so the task (that should be up for retry) gets stuck in the queued state. Oct 26, 2024 · When a task fails in Airflow, there are several strategies for recovery depending on your needs. I managed it to retry the start_job task using the on_failure_callback of the wait_for_job sensor task. The Dag has been created like below: default_args = { 'catchup': False, 'depends_on_past': False, 'start_date': datetime(2022, 1 Dec 27, 2018 · This command clears the task test_resubmit. 1. process_1_2 and it will run successfully, however its downstream (i. For one of the tasks, I want to retry it 5 times in case of failure in airflow. Go to the DAGs screen, where you can see the currently running tasks. Invoked right before the task begins executing. For example: Dec 4, 2020 · How to use a different retry delay in every Airflow task Bartosz Mikulski 04 Dec 2020 – 1 min read When we configure an Airflow DAG, we set the default values of various properties, for example, the retry delay. e. Invoked when a task misses its defined SLA. We advise against using dynamic start_date and recommend using fixed ones Mar 19, 2024 · This parameter specifies how many times Airflow should retry a task if it fails. Essentially, for any exit code other that 0, airflow will retry the task on the basis of retry value configured. Provide details and share your research! But avoid …. Jun 1, 2015 · If it deduces that it is allow to retry again retries < max_retries-1 and the state is failed, it will change its state, add 1 to retries, and pass the instruction to the executor. Invoked when the task is up for retry. 0 update, I understand that task group is a substitute for subdags but is there a way to retry a task group after one of its tasks fails? I have looked for this information on docs and blogs but I have not got With the @task decorator, you can turn any Python function into an Airflow task: from airflow. Of course this also means that you can view them in the actual log files themselves. exceptions import AirflowFailException def task_to_fail(): raise AirflowFailException("Our api key is bad!") If you are looking for retries use AirflowException :- Example:- Dec 12, 2018 · I resorted to reading the source code, and found that Airflow treats up_for_retry tasks differently if they are part of a backfill DAG run. Oct 25, 2022 · However, Airflow by default will only retry the Sensor task without retrying to run the Run task. How to reproduce. This SO post suggests using the GUI to "clear" failed task: How to restart a failed task on Airflow Feb 27, 2018 · Then for my task that runs subdagoperator, it has: on_retry_callback=callback_subdag_clear, It now clears out the task instance history of each task and re-runs each task in the sub dag up to the number of retries in the main dag. default_task_retries or 0 by default, so if you have retries > 0 and the zombie tasks are passed directly to failed, it could be a bug. models. TaskFlow uses XComs behind the scenes to pass data between tasks, removing the need for manual XCom management: Jun 24, 2022 · Hi I'm currently running airflow on a Dataproc cluster. By default it will also clear downstream tasks recursively, but you can change that with the option selections. sleep(300) in either of these params of Task 1. Versions of Apache Airflow Providers. I would like to perform some logic if the exception of the original failure is of a certain type. First state: Task is not ready for retry yet but will be retried automatically. No response. The order of your tasks is as follows: task_1 >> task_2 >> task_depends_on_previous_tasks And you want to retry task_1 and task_2 sequentially when task_depends_on_previous_tasks fails. returncode: raise AirflowException("Bash command failed") This indicates that unless exit code is 0, airflow will mark the task as failed for all other exit codes. No Sep 23, 2024 · How to Use Task Groups in Airflow? Advanced Apache Airflow Patterns: Retry & Failover, SLA Monitoring, and Sensor Tasks. Airflow Scheduler. com When a task fails, Airflow can automatically retry it based on the parameters defined in the task's configuration. Oct 14, 2024 · To better understand Airflow Task Instances, you can click on the topics given below. I fixed the bug that caused some tasks to fail and I would like to re-run ONLY FAILED TASKS. python import PythonOperator from airflow. but the first four tasks never get rerun. Alternatively, if retries == max_retries - 1 the scheduler will set the status of the Task to failed, notify that the task has failed, and not retry the task. Airflow 2. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. airflow do some unwanted thing that directly to run the last task and pretended it has rerun About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Description - How to run multiple ExternalPythonOperator (I need different packages / versions for different DAG tasks) after each other in serial without being dependent on the previous task's success "upstream_fail". See full list on stackabuse. All it does is to check if a hive partition exists. Airflow will find these periodically, clean them up, and either fail or retry the task depending on its settings. Problem Statement. Below is info from Airflow documentation May 22, 2018 · if sp. You have two ways of doing this: A. – Dec 23, 2021 · Is there any difference between the following ways for handling Airflow tasks failure? First way - def handle_failure(**kwargs): do_something(kwargs) def on_failure_callback(context): Jan 24, 2018 · I set up a conditional task in airflow described here. Nov 1, 2022 · Description How to run multiple ExternalPythonOperator (I need different packages / versions for different DAG tasks) after each other in serial without being dependent on the previous task's succ If task A depends on task B and their start_date are offset in a way that their execution_date don’t line up, A’s dependencies will never be met. Feb 13, 2020 · from airflow. Oct 16, 2024 · Hi, in Airflow auto restart is implemented only for tasks, but you can manually clear the first task in the UI and Airflow will restart it and all downstream tasks. This command will restart the specified task in the given DAG for the specified execution date. task_group, where self is a TaskInstance) then we should somehow enqueue again all upstream tasks in this task group. utils. Task C - Modify config file parameter x. On an hourly cron, if the task retries/fails 3 times, I don't want to wait till the next hour for the DAG to retry. dates import days_ago def conditonnal_retry(value=True): if value: return "retry should occur if dag run fails" else: return "no need for a retry if dag run fails. Oct 18, 2020 · I have a airflow dag with many sub-tasks, I know when certain tasks fail they can be re-run in 5 minutes, while other tasks can be re-run in 60 minutes. Similarly, restarting a failed task will log the new runs in a new tab. When something fails, we want to be notified, or make a specific action: I have tried via decorator def on_failure_callback(f): @wraps(f) def wrap(*a Feb 2, 2021 · It is possible but I would be careful about getting into an endless loop of retries if the task never succeeds. Feb 13, 2019 · You can make use of on_failure_callback and on_retry_callback params of BaseOperator to push the value that you want to persist as xcom. UPDATE: do NOT use this as pointed out by @Vit. For example. My DAGs used to run fine but facing this issue where tasks are ending up in 'retry' state without any logs when I click on task instance -&gt Nov 14, 2022 · I have a task that is configured to retry 3 times. When a task fails, Airflow can be configured to retry the task automatically, which can help to overcome transient issues without manual intervention. Then, you should set retry_upstream_depth as 2. ai. db import create_session def rerun_dag_task(dag_name, task_name): dag_runs = DagRun. Aug 29, 2018 · We are running airflow version 1. Oct 19, 2021 · First, In Airflow downstream task can not effect upstream task. 0. See Schedule DAGs in Airflow; Automatically retry tasks In Airflow, you can configure individual tasks to retry automatically in case of a failure. Original point: on_success_callback / on_failure_callback: Depending of whether Task 2 is supposed to run upon success or failure of Task 1, you can pass lambda: time. Oct 11, 2019 · I know that it is possible to retry individual tasks, but is it possible to retry complete DAG? I create tasks dynamically, that is why I need to retry not specific task, but complete DAG. Clearly Airflow did not meant for you to clear tasks in Running state however since Airflow did not disable it either you can use it as I suggested. In that case, we should wait for DAG A to run again before retrying Task B. Please refer the below answer for retrying a set of tasks/whole-dag in case of failures. I say "somehow" because I'm not sure how we should update database state. Feb 2, 2018 · The operator has set retries and retry_delay. Instead of manually restarting failed tasks, Airflow provides a built-in retry and failover mechanism. Here are some other ways of introducing delay. So I'd love to retry the same task on failure, but with a changed value for this parameter. Using DAGs Screen; Setting the Airflow Task to a Failed State; Method 1: Using DAGs Screen. Assuming structure of: taskA >> taskB >> taskC >> taskD then if taskB is successful and taskC failed. Jul 21, 2021 · I have a dag with multiple tasks. there are 5 tasks this day. The default number of times a task will retry before failing permanently can be defined at the Airflow configuration level using the core config default_task_retries. So if you run your task at 7AM, and want it to end at 9AM, then set the timeout to 2 hours. In order to achieve this I tried to pass: on_retry_callback=lambda context: reset_and_retry_tg(context, group_id) Jun 11, 2018 · You can run a second "Fail Check" DAG that queries for any task instances where the task_id matches what you want and the state is failed using the provide_session util. This doesn't seem to be supported. 1. If you are looking to delay a task, for example running a daily task at 2AM, look into the TimeSensor and TimeDeltaSensor. Oct 27, 2024 · In the Airflow UI, when a task is marked as UP_FOR_RETRY, how I can see the time it will be retried next in the UI? Airflow Task failure/retry workflow. hozti kdsfjni fspsfa owtwsm kgcovw cazkiz zqunb upy btikl qokboc esfg fdm konl hlkm otqvu